Tyler Cowen suggests: ponder this photo for an hour.

From the article:
Gulls are utterly fearless, as shown by this remarkable image of a white-tailed eagle under attack.
Herring gulls dive-bomb predatory birds at a steep angle from above and behind, as they make a piercing shriek - "kaiow!".
The attacks typically occur when the gulls are defending themselves and are most frequently seen during the breeding season, when adults protect vulnerable offspring. Some gulls also defecate or even vomit on the predator for good measure.